A. Field of the Invention
The present invention generally relates to automatic dishwashers and, more particularly, to a new and improved dishwasher having a highly efficient pump for pumping washing and rinsing liquids into and out of a washing chamber of the dishwasher.
B. Description of the Prior Art
Automatic dishwashers are old and well known in the prior art. It is also well known to use a bi-directional pump in automatic dishwashers wherein operation of the pump impeller in one direction directs washing and rinsing liquids into the washing chamber and operation in an opposite direction discharges the waste liquids through a drain line running out of the dishwasher cabinet. Centrifugal pumps having dual outlets for use in dishwashers are disclosed in U.S. Pat. No. 2,838,002 to Cohen and U.S. Pat. No. 2,883,843 to Bochan.
Other prior art patents are also of interest. For example, the Luenberger U.S. Pat. No. 2,633,392 discloses a thrust bearing for a shaft of a pump impeller. The Killane U.S. Pat. No. 3,323,650 discloses a rotary pump for a marine chlorinator wherein the impeller assembly of the pump is assembled through the inlet of the pump housing. The Blum U.S. Pat. No. 3,347,475 discloses a centrifugal pump having an impeller with a circular impeller plate and spirally extending blades of tapered thickness joined integrally therewith. The Bassani U.S. Pat. No. 3,680,826 discloses a cup-shaped sealing member of resilient flexible material which is securable to a peripheral wall and extends sealingly into the open side of a hollow access box to prevent intrusion of liquid into the interior of the box.
The Smith et al U.S. Pat. No. 3,810,480 discloses a dishwasher having a reversible, dual cavity pump assembly wherein the output of one cavity is in communication with a fluid distribution system and the output of the other cavity is in communication with an external drain conduit. The Spiegel et al U.S. Pat. No. 3,854,762 discloses a dishwasher having a rotary handle door latch for sealing the opening of a cabinet of a front loading dishwasher. The Hahn et al U.S. Pat. No. 3,981,456 discloses a dishwasher having a pal, such as polypropylene. The housing 50 includes an inner half or section 52 disposed adjacent to the motor 36 and an outer half or section 54 securely joined thereto, for example, by a heat sealing peripheral joint 56. Together the housing sections 52 and 54 form an involute pump chamber 58 (FIG. 2) about the rotatable impeller 42. The pump housing 50 has a first, relatively large, tangentiaa recirculating pump for swimming pool water; and the Meyers U.S. Pat. No. 4,448,359 discloses a combination drain pump and grinder for use in a dishwasher.
Although dishwashers commonly include a centrifugal type pump for pumping washing and rinsing liquids into and out of a washing chamber, to applicant's knowledge none includes a pump having both an impeller which is mounted for free-floating longitudinal sliding movement on a motor driven shaft so that the impeller may be readily inserted into the pump housing through the inlet opening of the pump and a bearing mount removably disposed within the inlet opening of the pump to provide a closure wall spaced apart from the impeller by a desired clearance or gap to provide for maximum pump efficiency. Such a structure would facilitate both the initial pump assembly and its disassembly during maintenance or repair operations.